WO2019096850A1

WO2019096850A1 - Sterile container with gas exchange device and method for adjusting the latter

Info

Publication number: WO2019096850A1
Application number: PCT/EP2018/081241
Authority: WO
Inventors: Stefan Schuster
Original assignee: Aesculap Ag
Priority date: 2017-11-20
Filing date: 2018-11-14
Publication date: 2019-05-23
Also published as: DE102017127289A1

Abstract

The present invention relates to a method for adjusting a gas exchange device of a sterile container (1) which is used in the steam sterilization of sterile material such as surgical instruments, and to a sterile container (1) with an inlet valve (6) or with a steam inlet device (5) like an inlet valve, wherein a valve opening pressure of the valve (6) can preferably be adjusted, or is adjusted, on the basis of a predetermined steam application time (t0) and a predetermined steam pressure (p0).

Description

Sterile container with gas exchange device and

Method for their adjustment

description

The invention relates to a setting method for a gas exchange device of a sterile container, which is used in the sterilization of sterilized sterile instruments such as surgical instruments, and a sterile container with a steam set according to set, wherein a valve opening pressure of a valve is adjusted based on a pre-determined Dampfbeaufschlagungszeit and a pre-determined vapor pressure, is.

Background of the invention

Common sterile containers consist of a tub, which can be closed fluid-tight with a lid, the container, for example, filters,

Germ retention systems and valves and use with various accessories, such as baskets, may be provided. In addition to sterile storage, sterile transport and provision in the OR, sterile containers are used in particular for the sterilization of sterile goods, such as surgical instruments, by steam sterilization.

In the steam sterilization sterile containers are used, which in one

Sterilizer or autoclave together with their load, so essentially the sterility contained therein, from room temperature to the sterilization temperature, which is usually between 134 ° C and 137 ° C, must be brought. This happens because the steam in contact with the sterile container and its contents, its energy, essentially the enthalpy of vapor release, and heated the sterile container and its contents. In this process, the vapor condenses on the surface of the sterile container and its load. The resulting amount Condensate depends on the mass of the container and its load, as well as the starting temperature of both. Often, the amount of condensate formed is too large to remove them by re-evaporation during the process again from the sterile container.

State of the art

As already described, in steam sterilization, condensate accumulates within the sterile container, which must be removed from the container, the amount of condensate may be too large to dry by re-evaporation alone. The known state of the art, which deals with the solution of this

Problem considered, here are ways to derive the condensate resulting from the steam sterilization from the container.

An example of such a sterile container is disclosed in DE 41 11 077 A1. This shows a sterilization container used in the steam sterilization, the bottom of which falls off towards the center to collect accumulating condensate, and is supported by a base, wherein the center, or at the lowest point of the soil, a

Condensate outlet or outlet valve is arranged. This Kondensatablass- or outlet valve opens and closes a drain opening abruptly by a

Snap-action switch made of thermo-bimetal for exceeding or falling below certain, within a wide range adjustable temperature limits (eg 110 ° C / 120 ° C / 130 ° C), wherein when closing the Kondensatablass- or exhaust valve, a gas-tight seal of the container under residual vacuum will be produced. In addition, as a further functional component of a known sterile container usually also a sterile filter (or a labyrinth system) is arranged, which allows a media exchange of the interior of a Sterilkontainers after sterilization with the environment to allow pressure equalization during cooling of the container. Otherwise, the sterile container could be mechanically deformed during cooling. Another example is shown in EP 2 366 410, which shows a pressure-controlled condensate drain valve which is located in a recess in the bottom of a

Sterile container is arranged and, for example, at about 1, 8bar opens.

However, the described prior art has some disadvantages.

For example, additional components are required for this, such as pressure cans or bimetallic springs, which complicate the assembly, the overall design and the maintenance of the system. Furthermore, an additional opening in the bottom of the container is needed, which must be additionally sealed and thus not only makes the cleaning of the sterile container consuming, but may also have a negative impact on the sterile barrier result. In addition, to ensure that the condensate drains, the bottom geometry of the sterile container is necessarily such (for example funnel-shaped) designed that the condensate to the

Condensate drain valve is passed out. This design of the bottom geometry of the sterile container must be supported for example by feet or a surrounding frame and thus has the consequence that the usable space is reduced within the sterile container and the structural design is complex.

Description of the invention

The invention has for its object to provide a method which makes it possible to avoid the disadvantages described above. A further object is to provide an alternative apparatus which minimizes a build-up of condensate in a sterile container during a steam sterilization process but which does not have the disadvantages described above.

This object is achieved by a device with the features of claim 1 and by a method with the steps of claim 9. Advantageous embodiments are the subject of the dependent claims.

In contrast to the prior art, which deals exclusively with the derivation of the resulting condensate and thus, so to speak, only the symptoms the basic idea of the present invention is to already minimize the formation of condensate within the sterile container. Accordingly, in the context of the present invention, causes of condensation formation and possibilities for minimizing or even preventing them have been considered:

Since the amount of condensate of a mass of material to be heated and an initial temperature of this material is dependent, the underlying idea is to minimize the accumulated in a container interior amount of condensate by the material to be sterilized, especially the container material is preheated on the outside, before the Container surrounding hot steam in the

Container interior flows. It was recognized that it may already suffice to preheat only the sterile container itself, since its heating causes a large part of the resulting condensate. Instead of this, an additional

Procedural step e.g. provided in the form of a separate preheating or other, additional elements (such as heating elements) use, has been recognized according to the invention that by a simple adaptation or retrofitting the existing system and / or the existing steam sterilization process can be converted in such a way that with low Expense in the conventional steam sterilization an additional intermediate step is made possible. This

Intermediate step is that the steam is initially brought as possible only from the outside with the sterile container in contact and this is thereby preheated as much as possible from the outside, before the steam then penetrates into the sterile container and heated therein stored sterile material.

In principle, this basic idea according to the invention could be implemented in practice by providing the container with a timed opening mechanism for the steam inlet, which would be complicated and expensive. Therefore, another solution is favored according to the invention:

According to one aspect of the present invention, entry of the steam into the sterile container is delayed as long as possible by the container with a (in the unactuated state tightly closing) (steam) inlet valve preferably the seat valve type is / retrofitted / is adjusted, the valve opening pressure is that it is significantly higher than that required with conventional sterile containers Inlet pressure, which is usually required to overcome the flow resistance caused by inlet filters and is typically 10mbar to 20mbar. This ensures that the largest proportion of the condensate, which arises during the heating of the sterile container, already formed on an outer side of the sterile container. In the sterile container itself collects in the ideal case, only the condensate that arises in the heating of the Sterilguts in the sterile container, which through

Re-evaporation can be dried easily.

According to another aspect of the present invention, the object is achieved by an adjustment method for a gas exchange device of a sterile container, which is used for steam sterilization of sterilization goods stored in a sterile container, preferably medical instruments, within an autoclave, wherein the following steps are carried out:

First, if necessary, a Dampfbeaufschlagungszeit is vorermittelt that at a

predefined steam feed rate in the autoclave is required to that in the

Autoclave inserted sterile container outside the sterile container to heat up to a certain sterile container temperature. Alternatively or additionally, the temperature rise of the container wall can be measured until it has reached or is close to the particular sterile container temperature. This particular

Sterile container temperature preferably corresponds substantially to the

Sterilization temperature. Upon reaching the determined sterile container temperature, a prevailing vapor pressure within the autoclave is subsequently determined. Finally, arranged on the sterile container valve / steam inlet valve and / or valve-like steam inlet device is set so that a

Valve opening pressure substantially equal to the pre-determined vapor pressure.

As a result, as already explained above, it is achieved that in the

Steam sterilization process, the steam enters the sterile container only when it is already sufficiently preheated from the outside and thus the in the

Container interior self-accumulating amount of condensate is minimized. Here, the steam supply rate may be constant or follow a predetermined sequence.

Reference should be made to the following technical contexts: There are basically at least two screws that can be turned to achieve that the steam heats the sterile container as far as possible from the outside, so first comes into contact only from the outside with the sterile container.

The first is the valve opening pressure of the container-integrated (inlet) valve, which delays as much as possible the penetration of steam into the container, allowing it to temporarily heat the container from the outside only. The possible opening pressure (differential pressure between the container interior and the chamber of the steam sterilizer) is dependent on the pressure stability of the sterile container and is in many commercially available sterile containers at about 60 mbar. Will the

Differential pressure greater, there is a risk of a possible mechanical

Damage to the container (the container is pressed together). Is the

Opening pressure (differential pressure) much smaller, the steam can penetrate into the container more or less instantaneously, so that the container itself is heated not only from the outside, but also at the same time (and not delayed) from the inside and thereby creates condensate inside ,

The second set screw is the pressure gradient set on the steam sterilizer (rate of pressure change). This is a measure of how quickly the steam flows into the sterilization chamber.

According to DIN EN 285 (standard for large steam sterilizers), this may not exceed 10 bar / min. lie. In modern sterilizers this is in practice at about 1 bar / min.

If the pressure gradient is high, the opening valve on the sterile container also quickly reaches the opening pressure and the steam has little time to heat the sterile container only from the outside. At a low pressure gradient, it takes longer for the valve opening pressure to be reached. Thus, the steam has more time to heat the sterile container only from the outside. If the pressure gradient is much lower than 1 bar / min., The steam has more time to heat the sterile container only from the outside, but at the same time increases the duration of the Sterilisationszyklusses. In practice, you will therefore prefer nothing or only little change on this screw, especially since this is possible only by the manufacturer of the steam sterilizer itself and not by the user.

The object is therefore preferably achieved by setting the valve opening pressure to be less than a (maximum) pressure stability of the sterile container and preferably in the range from 40 mbar to 60 mbar, more preferably between 45 mbar and 55 mbar. The preferably indicated range here is an area which is based on the stability of conventional sterile containers. Accordingly, the valve opening pressure of the valve to be adjusted is adapted to the respective sterile container and can also be adapted to other differently stable sterile containers.

The object is preferably achieved by providing the valve and / or the valve-like vapor inlet device with a diaphragm which has a predetermined passage area, preferably in the range from 0.5 cm ² to 10 cm ² , more preferably between 1.0 cm ² and ² cm ² , lies. More preferably, the aperture is provided on the sterilization container by a perforation field through which the steam enters the sterile container. Even more preferably, the perforation field consists of one or more passage openings.

The passage area of the diaphragm here denotes the size of the opening of the diaphragm, which is released when the valve is opened.

The differential pressure setting on the sterile container is therefore preferably pre-set via the (inlet) valve, which is preferably designed to seal the steam inlet in the unactuated state in a sealed manner.

Normally, sterile containers have a filter arrangement at the steam inlet. The flow resistance of the filter used therein is usually so large that it plays virtually no role in the sterilization process and how a dense material can be considered. Only at low rates of pressure change, such as during cooling of the sterile container after sterilization, outside of the

Steam sterilizer are available, a pressure equalization through the filter is possible. Therefore, in the context of the present invention, it is also possible to provide a filter with such flow resistance properties as a valve body, by means of which the valve seat of the steam inlet valve according to the invention can be closed sealingly in the unactuated valve state and lifts from the valve seat upon reaching the aforementioned differential pressure, starting a steam flow from the environment into the container interior. That is, a filter with the described resistance characteristics acts in the steam sterilization as the inlet valve sealingly closing valve body and in the subsequent

Cooling phase as outlet shutter for a slow pressure equalization between

Container interior and environment through the filter material.

More preferably, the permeability of the filter is adjusted so that it is sufficiently large, so that outside of a sterilizer / autoclave during the cooling phase, a sufficiently fast pressure equalization can take place, so that a valve opening pressure is not reached.

In the above-described advantageous embodiments and the individual units described therein, such as the filter, the orifice or the inlet valve is in terms of advantages and possible embodiments and

Properties of these features in the following description section, which describes these units as parts of a sterile container according to the invention, referenced.

By a trained as described above sterile container / sterile container is achieved according to the invention that the Dampfeinlassvorrichung during the

Steam sterilization remains closed until within the

Sterilizer / autoclave on the steam inlet device which has set the selected differential pressure. At this time (a few seconds after the steam inlet in the autoclave or even less), the sterile container is already heated by the contact with the steam from the outside and the resulting condensate has formed only on the outside. Only then, with reaching the set

Pressure difference, opens the Dampfeinlassvorrichung (the inlet valve), steam flows into the sterile container and also heats the sterilizing material therein. Advantageously, only a comparatively small amount is formed

Condensate in the container interior, which in a later drying

can be re-evaporated.

In addition, advantages of the disclosed sterile container according to the invention are that no / a few additional components / groups are necessary, since only system components which are required anyway are essentially used, which by means of a corresponding adaptation / change to an additional, new one

Assigned by purpose or by a few items, such as. the additional arrangement of a valve body must be supplemented. Because of this, for example, retrofitting existing sterile containers is easy.

The sterile container can be used with various accessories and in various variations. The valve according to the invention can only serve for the steam inlet and open inwards for a flow or can open in both directions at a certain pressure difference. In this case, a valve opening pressure for

Flows into the container interior may be equal to or different than a valve opening pressure for flows out of the container interior. Further, a valve having a predetermined (fixed) valve opening pressure may be used or an adjustable valve may be used. It is also conceivable, however, a controllable valve which is switched depending on sensor data such as pressure and / or temperature sensors, for example, sterile container-related data. The filter can be both a disposable and a reusable filter. The filter holder may be part of the valved vapor passage device. Further, the filter holder can support structures to protect the filter from excessive buckling

Protect pressure differences or other external forces.

Preferably, the sterile container further comprises the upstream of the inlet valve aperture. More preferably, the aperture has a predetermined passage area, which is preferably in the range of 0.5 cm ² to 10 cm ² , preferably between 1, 0 cm ² and 2 cm ² , as already mentioned above.

When the pressure in the autoclave rises, the steam inlet into the sterile container is additionally regulated via the orifice. In particular, the volume flow of the penetrating vapor can be adjusted by the passage area defined by the diaphragm or limit. The screen may in this case be mounted on the filter holder, be mounted directly on the sterile container or be integrally formed with this, or the container trough or the container lid. Further, it may be disposed above or below the filter.

More preferably, in the sterile container, the diaphragm is provided by a perforation field. In addition, the perforation field preferably consists of one or more passage openings.

It is advantageous that the perforation can be particularly simple and inexpensive formed as part of the container wall or the container lid. Furthermore, the perforation field can advantageously serve as a support structure for the filter, and protect it against excessive curvature by pressure differences or against other external forces. The passage openings may be, for example, lamellar, slits, round or square.

Preferably, in the sterile container, the filter is fixed in the filter holder. The filter or sterile filter is for gas exchange in the container outside the sterilizer, e.g. during cooling of the sterile container after sterilization advantageous, since in this way a pressure equalization can take place without a re-germination of the

Container interior can take place. The filter according to the invention is designed on the one hand to withstand a corresponding pressure and on the other hand to be permeable enough to prevent the achievement of a valve opening pressure outside of the autoclave.

figure description

The invention will be described below with reference to preferred embodiments

described, wherein features of various embodiments can be interchanged and / or combined. It is understood that details of the preferred embodiments described may not be construed as limiting the invention per se and may be obvious to those skilled in the art various changes, modifications and / or equivalents, all as such in the Within the scope of the invention defined by the appended claims.

Fig. 1 shows a sterile container with a valve-like steam inlet device

Fig. 2 shows a valve-like steam inlet device

Fig. 3 shows schematically a sterile container with a valve

4 shows a flowchart describing the setting method.

Fig. 1 shows a sterile container 1 for use with the described method with a container trough 2 and a container lid 3, which by a

Locking mechanism 4 are coupled fluid-tightly with each other. In the lid, a valve-like steam inlet device 5 is mounted as part of a gas exchange device, which may also be designed as a germ retention system and may be permanently installed or removable.

FIG. 2 shows a valve-type vapor inlet device 5, which is a combination of a seat valve type inlet valve 6 (FIG. 3) and a filter assembly 7, 8, 9. It has a flat, disc-shaped filter 7, a filter holder 8 and a diaphragm 9. The filter 7 is arranged in a filter receiving portion 10 of the filter holder 8. The aperture 9 is located in front of the filter 7 and is attached to the filter holder 8, for example by clamping. This serves as a cover for the

Filter holder 8. Furthermore, the diaphragm 9 has a perforation 11 with passage slots and an edge, the latter being designed to clamp the diaphragm 9 in the filter holder 8. The valve-like vapor inlet device 5 is at the

Container lid 3 is arranged, which on the container trough 2 through the

Locking mechanism 4, which has striker, is attached and the

Container trough 2 closes fluid-tight. In this example, a valve-like

Steam inlet device 5, the filter holder 8 is formed so that it forms together with the filter 7 and the diaphragm 9 held in it a pressure relief valve or an inlet valve, preferably the seat valve type. In other words puts in the preferred embodiment of the filter 7 is a valve body which is pressed resiliently against a valve seat (valve inlet opening). For this purpose, the filter holder 8 is mounted springs or has an internal spring property. From the resulting spring force on the filter 7 and the surface of the filter 7 and the cross-sectional area of the valve inlet opening results in the opening pressure of the valve.

If the pressure rises outside of the sterile container 1 and reaches one

predetermined pressure difference relative to the container interior 12, the filter 7 (in the function of a valve body) pressed against the aperture 9, which in turn pushes the container lid 3 movably and resiliently mounted filter holder 8 of the inner lid surface and thus releases a flow path for pressure equalization. In the closed position (unactuated position) springs push the filter holder 8 against the container lid 3 to close the inlet valve, but the filter 7 is designed so that even in the closed state of the inlet valve a (slow) gas exchange between Exterior 13 and container interior 12 only through the filter 7 therethrough, whereby after sterilization a

Sterile condition of the container interior 12 is maintained.

As an alternative to a combined system shown by way of example in FIG. 2, a valve 6 provided with a separate valve body and separate from a filter arrangement 7, 8, 9 can also be used. 3 schematically shows a sterile container 1 for use with the described method, with a container trough 2 which is closed by a closing mechanism 4 with a container lid 3.

In this case, an aperture 9 and a filter holder 8 are mounted on the container lid 3, or formed with this, and a filter 7 is held by the filter holder 8. In addition, a valve 6 as a separately formed element in the

Container lid 3 arranged. In this case, the valve ensures the pressure equalization when exceeding a certain pressure difference of the outer space 13 relative to the container interior 12 and allows the influx of steam during steam sterilization. In the sterile condition, however, the valve is closed. 4 shows a flowchart for describing a possible method according to the invention. This is a method for adjusting the gas exchange device of a sterile container as described above, which is used in the steam sterilization of in-container interior sterile material within an autoclave.

- At a predefined or adjustable steam supply rate in the autoclave optionally a Dampfbeaufschlagungszeit tO vorerittelt, which is needed so that the sterile container 1 from the outside to a certain

Sterile container temperature Ts, preferably the sterilization temperature, is heated (S1). During this heating steam condenses on the outside of the sterile container 1, while still forms in the sterile container interior no condensate.

- When the specified sterile container temperature Ts is reached during the heating process, a vapor pressure pO within the autoclave, or a

Differential pressure between the container interior 12 and the outer space 13, which is the autoclave interior, (pre) determined (S2). It must be noted that the pressure has a certain value which results from the

Pressure stability of the sterile container 1 and / or the filter 7 results, does not exceed.

- Based on this predetermined vapor pressure pO arranged on the sterile container 1 inlet valve 6, and the valve-like steam inlet device 5 is set so that the valve opening pressure substantially the (pre) determined vapor pressure pO and the valve 6 opens upon reaching this vapor pressure pO.

In this way, only after the sterile container 1 itself has already been heated from the outside, steam to flow into the container interior 12 and heat the sterile material contained therein, wherein steam ideally only condenses on the sterile and no further on the inner walls of the sterile container 1

Condensate precipitates. Consequently, the amount of condensate formed within the sterile container 1 is only as great as is unavoidable in the steam sterilization of the sterile product and can easily be re-evaporated. An additional Condensate drain valve is thus not necessary to dry the container interior 12 of the sterile container 1, even at high loading.

At this point, it should again be noted that the opening pressure of the valve is predetermined / limited by the stability of the sterile container and especially in the case of a sterile container made of aluminum should be at a maximum of about 60 mbar. The steaming time results from this value and the pressure gradient with which the steam sterilizer operates. At a pressure gradient of about 0.9 bar / min. this would be about 4 seconds. During this time, the sterile container 1

heated exclusively from the outside.

The pressure equalization by steam, which passes through the filter in the sterile container 1 during this heating phase, is negligible due to the flow resistance of the filter. Therefore, the filter 7 can be used as a valve body for quasi-tight closing of the inlet valve.

In summary, the present invention is a

Setting method for a gas exchange device of a sterile container (1), which is used in the sterilization of sterile sterilized such as surgical instruments, and a sterile container (1) with a valve (6) and / or a valve-like

Pertaining to steam inlet device (5), wherein a valve opening pressure of the valve (6) is preferably set based on a predetermined steaming time (t0) and a predetermined vapor pressure (p0).

LIST OF REFERENCE NUMBERS

1 sterile container

2 container trough

3 container lids

4 locking mechanism

5 Valve-type vapor inlet device

6 valve (steam inlet valve)

7 filters

8 filter holder

9 aperture

10 filter receiving section

11 perforation field of the aperture

12 container interior

13 outdoor space (autoclave interior)

pO differential pressure (valve opening pressure)

Ts Specific Sterile Container Temperature (Sterilization Temperature) TO pre-determined vaporization time

Claims

claims

Sterile container (1) with a steam inlet opening characterized by an inlet valve (6) or an inlet valve-like vapor passage device (5).

2. Sterile container (1) according to claim 1, characterized in that the

Inlet valve (6) or the inlet valve-like vapor passage device (5) is formed according to the seat valve type.

3. Sterile container (1) according to claim 1 or 2, characterized in that the valve opening pressure of the inlet valve (6) or the inlet valve-like

Steam passage device (5) in the range of 40 mbar to 60 mbar,

preferably between 45mbar and 55mbar.

4. Sterile container (1) according to any one of the preceding claims, characterized

characterized in that the inlet valve (6) or the inlet valve-like vapor passage device (5) is preceded by a diaphragm (9) having a predetermined passage area, preferably in the range of 0.5 cm ² to 10 cm ² , more preferably between 1, 0 cm ² and 2cm ² , has.

5. Sterile container (1) according to claim 4, characterized in that the diaphragm (9) is provided on the sterile container (1) by a perforation field (11).

6. Sterile container (1) according to claim 5, characterized in that the

Perforation field (11) consists of one or more through holes.

7. sterile container (1) according to one of claims 2 to 6, characterized by a preferably plate-shaped or plate-shaped filter (7) which is fixed in a resilient or resiliently mounted filter holder (8) and adapted to act as a valve body of the inlet Valve (6) or intake valve-type

Serving steam valve device (5) of the seat valve type, by means of which the steam inlet opening of the sterile container (1) until reaching the

Valve opening pressure substantially sealing closes.

8. Sterile container (1) according to claim 7, characterized in that the filter (7) is adapted, with closed inlet valve (6) or closed inlet valve-like vapor passage device (5) a pressure equalization from the sterile container (1) to the outside to pass through the filter (7).

9. Setting method for a gas exchange device, in particular in the form of an inlet valve (6) or an inlet valve-like vapor passage device (5) of a sterile container (1) preferably according to one of claims 1 to 8, which for steam sterilization of stored in a sterile container (1) Sterilisationsgut, preferably of medical instruments, is used within an autoclave, with the following process steps:

- Steaming the sterile container (1) at a given or

adjustable steam supply rate into the autoclave until the sterile container (1) inserted in the autoclave is heated to a certain sterile container temperature (Ts), preferably substantially sterilization temperature, on the outside of the sterilizer container,

- Determining a vapor pressure (pO) within the autoclave, during the

Reaching the particular sterile container temperature (Ts) prevails and

- Adjusting the sterile container (1) arranged gas exchange device, such that their opening pressure substantially the pre-determined

Vapor pressure (pO) corresponds.

10. adjustment method according to claim 9, characterized in that the

Opening pressure is less than one, the pressure stability of the sterile container (1) is threatening pressure and preferably in the range of 40mbar to 60mbar, more preferably between 45mbar and 55mbar lies.